The last 110 years have seen the development of complex systems for global communication and entertainment using moving images. With the exception of some specialized systems, current imaging technologies record and display these images in only two dimensions. This limitation owes partly to the inability of current standard camera and display technologies to capture and to present the parallax information needed to produce true three-dimensional images.
True three-dimensional image displays can be divided into two main categories, stereoscopic or binocular and autostereoscopic. Stereoscopic techniques (including stereoscopes, polarization, anaglyphic, Pulfrich, and time-multiplexed (shuttering) technologies) require the viewer to use a viewing device, such as polarized glasses. Autostereoscopic techniques, such as holography, lenticular screens, parallax barriers, alternating-pairs and parallax scans produce images in a true three-dimensional illusion without the use of special viewing glasses.
Certain “stereo” techniques have been developed for producing and/or displaying a three-dimensional image. These techniques, however, may not be compatible with unaided broadcast television or standard motion picture projection systems. Rather, to produce the stereo imaging effect, these techniques require special display equipment or special glasses that must be worn by a viewer of the image. These limitations have confined these imaging techniques to highly specialized industrial, military, and novelty applications.
While a standard display cannot present a stereo image without special equipment, it can present an image with enhanced texture and depth. Parallax scanning lens technology can create autostereoscopic moving images with enhanced texture and depth on standard displays without the use of special screens or viewing glasses. Images can be recorded on normal film, video, or digital media using standard industry camera systems. Image enhancement may be accomplished entirely by the lens by parallax scanning during recording of the image or images.
Several systems have been developed to generate autostereoscopic moving images through the presentation of parallax information in the images. For example, autostereoscopic television and motion picture systems have been developed that alternately display views of a scene recorded by two cameras from different points of view. These systems may include two cameras to record horizontally, vertically, or a combination of horizontally and vertically displaced views of a scene. While these autostereoscopic approaches can produce images that provide a three-dimensional illusion when displayed, precision matching of the two cameras is required. Improper alignment of the cameras, lens mismatches in focal length and/or focus, camera chrominance and luminance mismatches, and misplaced convergent points all contribute to image flicker and instability, thereby limiting the commercial applications. Also, these systems required considerable operator skill to continuously adjust disparity, convergence and time-displacement rates of image recordings in the necessary coordinated manner.
To avoid the drawbacks associated with a two-camera autostereoscopic system, autostereoscopic methods and systems using a single camera/single lens have been developed. These single camera autostereoscopic systems can record images that, when displayed, may be perceived by a viewer as three-dimensional. In certain embodiments, these single camera systems record images while undergoing oscillatory parallax scanning motion. This parallax scanning motion can produce recorded images with the parallax information needed to create the perceived three-dimensionality of the images when displayed.
While these traditional, single camera autostereoscopic imaging systems may be effective in producing images that can be perceived in three-dimensions when viewed with the unaided eye, these systems are rather bulky and heavy, relatively complex in construction, and consume a significant amount of power during operation.
Moreover, subsequent systems depended on scanning iris mechanisms that included analog rotation actuators to move the iris leaves in a manner to that created a parallax scan. The size and weight of the actuators limited the number of iris leaves that could be used (e.g., four) to create a parallax scan. A simple four bladed (leaf) iris, however, resulted in a square aperture. This caused scene highlights not to match images recorded using standard “round” iris lenses. As a result, cutting (i.e., switching) between images recorded using standard lenses and parallax scanning lenses would generally appear mismatched and awkward. In addition, the analog actuators lacked the ability for self calibration, error correction or precision control.